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The proposed ICCT-controlled DSTATCOM-BESS system under current controlled operation is presented in Figure 4.3.

Figure 4.3 ICCT-based control algorithm for DSTATCOM-BESS.

The ICCT-based control algorithm consists of two components of three-phase reference currents with respect to phase-voltages, i.e. the in-phase component and the quadrature component. I* _sad, I*_sbd and I*_scd are the in-phase components of the reference source currents. These are required for charging the battery of the BESS system which supports active power to the connected load. However, the other techniques for the generation of reference source currents for maintaining power quality are well discussed in [24].

The single point operation of load levelling can be illustrated by assigning a constant value of I*_smd. However, the multiplication of the obtained value of in-phase voltage unit vectors (Ua and Uc) are calculated by dividing the AC voltages (Va, Vb, and Vc) using the peak amplitude (Vm), which provides the in-phase component of the reference currents (I*_sad, I*_sbd, and I*_scd). Also, estimation of the quadrature component of the source reference currents (I*_saq, I*_sbq, and I*_scq) is required for accurate control of the supply voltage at the PCC. Moreover, the quadrature unit vectors (Wa, Wb, and Wc) are perceived from the in-phase voltage unit vectors (Ua, Ub, and Uc). The peak amplitude of the voltage (Vm) is sensed at a coupling point and compared with the calculated reference voltage. This generates the voltage error. The obtained error is further passed through the proportional-integral voltage controller. The output of this controller (I*_smq) ensures that the AC voltage control and provides the amplitude of reactive current component required for the system. The multiplication of Wa, Wb, and Wc with I*_smq helps to estimate the quadrature component of the reference source signals (I*_saq, I*_sbq, and I*_scq). The addition of the quadrature component and in-phase component of the above-estimated reference signals provides the reference source currents (I*_sa, I*_sb, and I*_sc). However, the hysteresis-based current controller is implemented for the generation of gating pulses for the DSTATCOM-BESS system [25–27].